SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b4188e695e3dd614c76c28c660604a0c2cdd7445b313ec574136c38b3d1363f2' 
  AND token = 'j6mvspegFXcjo3YqDmSU6DRzYscNfwhHLL2B+HsyDAg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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