SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85715dd793fcd5d173719ad3202d76c5358c94c1955d39e678a0b80b424b2df8' 
  AND token = 'oVy9/3kKbBuGneW4Qs06Gp33WJI8rxoc+OhbxEQWmJo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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