SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '1fbe36372ab50dc5afd808f24e523a84bdba420fa90f36a498f66025652ec408' 
  AND token = '4ghZQ2X25lJT7h9Sa49xlKc2J+3AA+prKrb3BJbkgS4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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