SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9fb6fe4dcf190876ee596a278d3302c6f7b22933d6885eb0a29f7a08e2a34d9' 
  AND token = 'lagt/OMv052L1AOEJWmA2a1Sr4BahDwjCtUEPP/Ixn0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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