SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b4209c2b5d6fe3bdb3cb03690c1cb17a1db679374801647168f7c1560d7aa68f' 
  AND token = 'Rj8FLmtTHB08BStdPV74M5CK6rkiKKEitOzF/CAgde0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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