SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c7c604c7b48bd508f35526ff6a388def1914b7a382fdc01f2c1cbcd5db10b04' 
  AND token = '5deN7eiw3/L3Gqj9PV7UgAV1TE50wTz/gcdOZbGwliY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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