SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e51e1ddf2c9c18f24dd50bd933f3bea299a6f176b1a27b2b8d2b54d267efcac' 
  AND token = 'PCzjJGyB4gXTzv1/GQ/ilpw/lYM65oaR268/TvL5yXg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}