SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f872329295a304cf82a4fa1d9a0a93aecd856d65203fe3996e5fd463ba716197' 
  AND token = 'dbqw/zJp3ATOQBtby++ZVsLwobCJgSw1n6gmexL41EM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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