SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54b514461bda41bc8f997d02da8aeea832a996b124fbbe41de1a71bd8ddbccb1' 
  AND token = 'hTWbMOrpnXxr7GXF5+fEVvHMwD4zET2xEqeCGKhp5nk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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