SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a7ebfc50f6bd656d2bd6168ce4c728d66ba0dca51612a75ea1885139036b441' 
  AND token = 'kurwosKBihqnUNgLiHRNQV+lt71Jwp4rkDEyG/Po54s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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