SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11f56bf59d242eb28c555d53cf5553fec348f244dc50ec53a45711a3aecb000e' 
  AND token = 'L3NH2PbtVJeIxOdz+EFh99DIgdZjzpwpfju5SLFVAQg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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