SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e1b83e6937d9547fdbfff8277e502e36f4be68654a1aaecbafa21b5f26f15cf6' 
  AND token = 'nlfFFn6E2nx2dzkiNRLpaZ+ivKTc90ShDhEq4fzRnyI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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