SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9640579af91353aaa494d1a7ee896c94b73ca376884b2243d1ed746d3a5cc40c' 
  AND token = 'syZcL8jnELpoJ2FyWfnLz5W8xYjQEnevyLbE1rVYKHw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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