SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1f2e76975ddfbc586673f76a637f99ff21b85967c7aa24dc55a20d31364aeee' 
  AND token = 'ZZmeaGADIDfAAp3Dh+2102wXCfrvoEqDqsSRlYLEvGs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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