SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '465fc6b7ea84a40c004309d77c8df3d37a9a5c2d8f10a5e01a29903954c87f02' 
  AND token = 'VhfJhLz+kT3pvdhZTwTxNV2lEJ9j/LCrgDeAb+sJSho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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