SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f760023cb02371f0928dd1bf57a8b94e1eca1830ebdd3b4441ba58948ab3094' 
  AND token = 'hqKYPc0ml72O9XCDPHipQtCvBBq1dBTFTkNzTvbYylc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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