SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '1c1e4e3cc7f392bd4d657bcb293d089f1f39579565208e84bf4d39743ada9bf7' 
  AND token = 'dQ/RhxMZ5mKqxcklZw+WtdAHkvKmAu6D5pAr8uc7qAo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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