SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '13527fb1987ec371ab183c853a9f878197edf60b56717e0b55f26699f7bca837' 
  AND token = 'SkTpFDqDjvhHTEvFGILQSJwxbveFF4EVGsznCCBiNyY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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