SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ad4d3c9ba16773fbb0c026f221c9eff21362d6d8f643556bfcf12615912a6469' 
  AND token = 'cQZsOBg47mILqzxhUKTeniDcwI+yecgPb/MIFklhcbM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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