SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4d4056e7717d40acd301ad92e521528f5250e94e175537833fab32c98ca5c9a' 
  AND token = 'bOAuIYYEVyvcsgNNbdvI+BuFPICKrLG6CshVxMv7CB4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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