SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2970ab816b435ae8916fd2e0f9c07bda01885e8a4b0b2cd4c1131866e72177ec' 
  AND token = 'BH6rPbWwF6QlZ0vOlOvVFvlYy37+urHjk/DzeEqRrG8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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