SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'da65d487d2a1c69f89c6a74090ee82241b74fb6fd6139880e4b4c3e9abb0b596' 
  AND token = 'z/4KWQwjPsV79VA6lIF0EKTaEf/gwpiW0c2eZY/sBKw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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