SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e179e7911738b0c49459ce5ca81fb4b11ba559f831ba206d8e883000da473426' 
  AND token = 'XzEphm3MCnLdw6dn77io5BVLoA18P234SyiPq1MBXSY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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