SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0621cd5ca640d340fff8ba0d7a98d368082a1aaedd0a57eefc3f52e40899a4a' 
  AND token = 'eUwljj06F9QqzJxxJADQGJcDOmDrYQ+P1a4GOnx1Z4I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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