SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a4c43e8d2624484c2c0e3e12be9fbb69ddccdfd8a2c897650891561d7a41d03' 
  AND token = 'nYDgXZ0gj9S40cpUw4QWP3Qjv+KH82fW0x6isk+8Cv4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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