SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c030322897e82d230e875bf4d53bc505cd9e8977e723254a66b3b1878c78777' 
  AND token = 'ELxRZaDShhkGcOE2VEoZ46GL5+A/cgKnrsLfWAXJbjY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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