SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6faa06528c391e7af09a79162a1b6eaf51001ef6b5927d7670014e012c4da5b' 
  AND token = 'xq+/huyR2ULHUgg7MR23Lf6vUn5vEBKowTAU37zaM40=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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