SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '139fc92d48957451c896a98e709188241adb611f49a2dd6923488b516c20a0b3' 
  AND token = 'sG340fCISQ2huQAqvqFENsGPEmF91WBdvgIZ2nntREQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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