SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b3a94d0f48a997077fb2531f2a1c0a7da67f26823d8e48f8e32225b0b48fa1c2' 
  AND token = 'ulGHHKNO/8F3vWM/YLf+H3yH6rkDBEW42OGAxmzBMrs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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