SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd84e6a8ff4c2cd3a310177bf31f7736c536c6e878cab392f81bf7195de6b600e' 
  AND token = '3jJLBfkInJDDh5eBcfbpHEqGMveMhuZK7pvL4H3Zvqg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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