SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e6e04d2e380a859c26acfda998985bb1bafbd0283d5622860a28acb1eb74bc71' 
  AND token = 'JWdlaw/lun79HzoC7C3Tij0muF2ULBLdb9jc+vNC208=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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