SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '961de0952a3f40378b907ead6afc816bc9dd51db74373e59bd818f50a68c07a6' 
  AND token = '6VchNims00p+uhCujqi47geVKsr0IYkuPPFfzb7hQsw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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