SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '846d02dc035234ac757d7dc52c02cf1eec5d293526471b546cf280fdd0cd377a' 
  AND token = '/JCzBV/S0/Ms77s/yiDcYBQwnDCv4QKXbgHOmApDioY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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