SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '303aa4737d869dc73175f4c173308399d762ec4bd6309cd3aaf9a53479c19f7e' 
  AND token = 'gGp7caI6uOOcR9e1gC3EAoFh1GsHtM2fSs66CerZXRg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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