SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e2f56d92c31020dab15c2d86f39de7526a18c0fa4d9220d1b820c987d23b382' 
  AND token = '2+aTRW1fOxQ3m/jugoOWLPE640ybLqlsyHhqPvkMYSA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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