SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fa2118d0c9fc3d50bcc3cbd91a1a9e04a99f436268f33fea1173ce11e9888cd' 
  AND token = 'dZ/Og5zN2ZDHFW8XRA7WjAMQsxYttfMa+6p+B5T8gos=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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