SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c769f67d2fe21315dbfe70c2a5c23e8df8f763a3585b288211e30feadb67ef9' 
  AND token = 'fMyTo1Ff51U0BBE0B5EZn8LDLYzN0trn2DsMQLEqcjE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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