SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7076f860753811882fe504169d8d772be5bdbb795f5185beb3234fa4a6c863c' 
  AND token = 'uHugP4muFIQPmIvTqwGqAIebBJGSGzWpmfA0UoLWbY8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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