SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '339b1cf70e32fd0c494d73f763f2fa2888e41b8fba6a1de2c1b9e741051b7806' 
  AND token = 'myTqFcWCDKkmek2s4ejlZ8gvSmiWxTIzpufvrDL4TUc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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