SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c1d7863f5248a3c0a5967adebf7b7dcb690533df8562624a1d1a0f9948b62a8' 
  AND token = 'y+zmcZvksY4vkETKGLVwARIw9vJaZiqeQfUZGTFAiRk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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