SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b836263bec9f5917489288125757c5dbf514dbfceee0e5763eacc41f70510c21' 
  AND token = 'gVquif4Y4cBGGlgWxp8w3/vewS+eemuDAs2Usgzlt6k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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