SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15322d72e0cbd1cade27c1bef111a2a94ce5047dcd47e35c2002b5a1551d306d' 
  AND token = '2mAA8dYqFTbZ3DubKaFMk8y+9pw/LvKoESoncNHYP4E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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