SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '1b50e5423d6e3a4cde8b0555f06a2897dc168bbf80c5f25013dc9005fe902a76' 
  AND token = 'K5yQ1FaWk5rlSJoBiiRPfe58ZLMV3xpIaJOHRtdTH6M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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