SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7dbf4cbaf23ef57853845d8dd11a77981844d269241047ff589d2db21f63fcb5' 
  AND token = 'eI/01OGk2kOdCG5S9EjWXgshI7lHZkEche6YdXbT6YY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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