SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '276f0830bd3f996d00acec5c82d073676b8cd65d589774bbe4b7c49129835d0d' 
  AND token = '+ZVTJrX3glGlDgALacfL5cMKBRyfzP/Hp+ix/sJiCbo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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