SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b99da51d7252e4c993998536ca3a6f24beab7c16d87e6af13ed407cdf4e95c46' 
  AND token = 'HlUnRHDiMeS/jBVv0H7Qle3Q4iPr16frSYjwBsIJAbI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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