SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '41646db2ced5facec2d5d61a50826d0fb8378df199fac460f4309bc7b52361d2' 
  AND token = 'iznLF3HfAqUnmf8HV4RWnfCv4FkYHxBj5up4nleMGoY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}