SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9ce3dd022e252d9b7691e8048b3c877f82c969bdbf7e91af0b3621908474c22' 
  AND token = 'QZlM/kRYEGAQldmMwYB3FNYVMOR/ZirWathyHqnQQ/M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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