SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3d16f96e4d5b85b91ff87a623b08e42a1c7f25e9d1f2d98ccd7e14083f1a700' 
  AND token = 'yJ69ohWJRwVxzL+KV6x7OT/dcrhuXddPULH6qApzCA8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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