SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6da056b67fc9cb4c868578d0421dbf5d39b860a228639736371b12e9fc4e7d3' 
  AND token = '5H+kI4gFSvsYY9OXtKCCCEDY+6NLpxf1j6rjiiin/VQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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