SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe9df74447ca3071b083672abdcab4e25987c3402cb4a6dc8783f641275c09a1' 
  AND token = '3wBnpV3SikseUfpPfg+zcY+KLNkgumYJxit/LDEuxLo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}