SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a57430d8cf652d800c59bf87d22d4229f262fcbc7c63019a72033800c104372' 
  AND token = 'newdNRJrSR4Qig7gl4F6UxDYgr8aCjX16scqGHZWhBM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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