SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f5eabe9cc4fcd8fbdc5f4f9e6a0ceb1f60c693f0d87c2d4a1f5dad925a7739c' 
  AND token = 'dUW6uSthif0yBQ6y1rfgeLzObHjpCXp9yZpwLMLk2/A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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