SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c3e28c19c40917a2486de0217a7c3dd01e8f42c5977e81f54c85883da76f6571' 
  AND token = '+PhN1D9R6amdcY32nLZKKzCVrmG+UUqa5jmy+jwnEKM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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