SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '332f164382cc414fd34693e0366aeaab8078393e1d8e7aca0d8644aad096d388' 
  AND token = 'heH8kewU4XKNYrQM2prcQuPqoq/ZzbwOsmZtIYGvmwQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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