SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4697e34cb8129c84173c56a139d93d403e5a9100601f38c47ed3ca6330a27af6' 
  AND token = 'Op/iVObFKvfoeNLPNFvYCUaHwAM1f2cYfXq+Nrp9LTk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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